UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.47 Safari/537.36

Example URL:
http://jsbin.com/panopacimo/edit?html,output

Steps to reproduce the problem:
1. <div contenteditable="true">a<span style="unicode-bidi: bidi-override;">@a</span></div>
2. Put your cursor at the end of the text.
3. Press left, left, right.

What is the expected behavior?

What went wrong?
The browser hangs.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? Yes 

Chrome version: 51.0.2704.47  Channel: beta
OS Version: OS X 10.10.5
Flash Version: Shockwave Flash 22.0 r0

Also repros in canary 52.0.2735.0 and Safari 9. Does not repro in Firefox. So I'm guessing an old WebKit bug?

(Also, after pressing left twice the cursor is at the beginning of the input instead of between the first two chars which is surprising to me. Not sure if this is correct.)